1. Field of the Invention
This invention generally relates to a feed control system for controlling the feed motion of an object, such as a table, and, in particular, to a double motor feed control system suitable for use in controlling a relative movement between two objects, such as a table in an X-Y cross table assembly.
2. Description of the Prior Art
A feed control system for controlling the feed movement of a table relative to a base is well known. A typical prior art feed control system is disclosed in the Japanese Patent Laid-open Pub. No. 58-113653 which is hereby incorporated by reference. In the feed control system disclosed in this publication, a plurality of screws different in pitch or lead are formed on a feed shaft which is operatively coupled to a table to feed the table at a fast speed or slow speed selectively. In this case, however, since a plurality of screws or threads must be formed on the same shaft in series, the feed shaft tends to be longer, which, in turn, tends to make the entire system elongated in shape.